Virtually all computers include a low-voltage on/off switch or power button (hereinafter “power button” or “button”) configured so that a human user may manually activate the button to change the state of the computer from off to on or vice versa. In the vast majority of computers, the button is permanently mounted to the computer's enclosure at or near its exterior. For example, a very common configuration for desk-top and tower computers is shown schematically in FIG. 1. In the configuration of FIG. 1, a power button 100 is located on the front chassis wall or bezel 102 of an enclosure 104. Button 100 is directly coupled to the motherboard 106 by means of a 2-conductor cable 108. Motherboard 106, in turn, is connected to a DC supply output 110 of a power supply 112, which receives its power from an AC supply 114. Typically, sensing circuitry on motherboard 106 detects activity in power button 100 and causes the computer system to power up or down depending on its previous state.
Unfortunately, any such configuration wherein the power button is permanently mounted to the enclosure imposes constraints on where the computer may be located and how it may be oriented. In short, most prior art designs require that the enclosure be located and oriented such that the power button remains accessible to the user at all times. This makes it very inconvenient to deploy a prior art computer for applications requiring the computer to be located in an “out-of-the-way” location such as in a point-of-sale environment. On the other hand, such prior art designs are convenient when the computer is used in traditional desk-top or desk-side locations.
One or more “Macintosh” models from Apple Computer, Inc., provided a power button 200 that was permanently integrated with the computer's keyboard 202, as shown in FIG. 2. Signals describing activity on button 200 were relayed to circuitry within the computer's enclosure 204 by means of the keyboard's universal serial bus (“USB”) interface. The USB interface included a flexible cable 206 and a USB connector 208 designed to mate with a corresponding USB socket mounted to enclosure 204. While this configuration provided some flexibility regarding the location of the power button, in every case the button necessarily had to be co-located with the keyboard because the button was permanently integrated therein.